The EU's Michel Barnier and UK's David Davis have agreed to meet next week to start talks on Britain's departure from the bloc. Theresa May has still not sealed a deal for the DUP to support her minority government.

"David Davis, Secretary of State for Exiting the European Union, and Michel Barnier, the European Commission's Chief Negotiator, agreed today to launch Article 50 negotiations on Monday, 19 June," according to the statement issued on Thursday afternoon.

Since last Thursday's UK general election when the Conservative party headed by Prime Minister Theresa May failed to win a parliamentary majority, there have been concerns the start of the Brexit talks would have to be delayed.

May is believed to have reached a "broad agreement" with the DUP although a deal has yet to be announced. The state opening of parliament when the Queen reads a broad outline of the government's program is expected to take place two days late - on Wednesday.

Brexit negotiations: What are the key issues?

Two phases

EU leaders agreed to negotiating guidelines during a summit in April 2017 that divided the divorce talks into two phases. Phase I, in which both sides aimed to settle the basic terms of Britain's departure, started in July and ended with an agreement on "sufficient progress" in December. Officials are now holding Phase II negotiations on the post-Brexit relationship between Britain and the EU.

Brexit negotiations: What are the key issues?

The "Brexit Bill"

London agreed to a formula for calculating what it owes in its "divorce bill" to the EU in early December after months of haggling by British officials. The current EU budget expires in 2022 and EU officials have said the divorce bill will cover financial obligations Britain had committed to before triggering article 50. The final bill will reportedly total around £50 billion (€67 billion).

Brexit negotiations: What are the key issues?

Citizens' rights

Both sides agreed in early December that the 3 million EU citizens currently in Britain and the 1.1 million British citizens in the EU keep their residency rights after Brexit. British courts will have immediate jurisdiction over EU citizens living in Britain. But the EU's highest court, the ECJ, can hear cases until 2027 if British judges refer unclear cases to them.

Brexit negotiations: What are the key issues?

The Irish border

Britain and the EU also agreed in December that no border checks between the Republic of Ireland and Northern Ireland would return post-Brexit. How feasible the commitment will be is unclear, as Britain's commitment to leaving the EU Single Market and Customs Union makes it difficult to avoid customs checks at the Irish border.

Brexit negotiations: What are the key issues?

Transition period

Theresa May envisages a two-year transition period after March 2019. Both sides still have to hash out the details of the transition period in Phase II, including the exact end-date, whether new EU laws passed during the period will apply to Britain, and whether Britain can negotiate its own free trade deals. British officials hope to agree on the terms of the transition by March 2018.

Brexit negotiations: What are the key issues?

Trade

May has repeatedly said Britain will leave the European Single Market and the EU Customs Union. Leaving both could disrupt British-EU trade, but allow Britain to negotiate its own free trade deals and restrict EU migration — key demands by pro-Brexit politicians. London has said it wants to negotiate a new EU-UK trade deal during Phase II to minimize trade disruption before March 2019.

Brexit negotiations: What are the key issues?

Immigration

Britain has also vowed to restrict EU migration into Britain after Brexit. However, some British lawmakers are wary that a sharp drop in immigration could lead to shortfalls in key sectors, including health, social care and construction. The EU has warned that Single Market access is out of the question if London decides to restrict the ability of its citizens to live and work in Britain.

Brexit negotiations: What are the key issues?

Security

Recent terror attacks across Europe including a string in Britain underline both sides' support for continued security cooperation after March 2019. But access to EU institutions such as Europol and programs such as the European Arrest Warrant require compliance with EU laws. Whether Britain will still be compliant after it leaves is unclear.

Author: Alexander Pearson

Concerns for Brexit

A majority of voters in Northern Ireland - 56 percent to 44 percent - elected to stay in the European Union in last year's referendum. However the DUP backed the leave option.

Northern Ireland's frontier with the Republic will be the UK's only land border with the EU once the Brexit deal is completed.

DUP leader Arlene Foster has said she is keen to secure a "frictionless" border with Ireland and has spoken out against a "hard Brexit."

"What we want to see is a workable plan to leave the European Union, and that's what the national vote was about – therefore we need to get on with that," Foster said recently. "However, we need to do it in a way that respects the specific circumstances of Northern Ireland, and, of course, our shared history and geography with the Republic of Ireland." The DUP is believed to want a comprehensive free trade and customs agreement with the EU and arrangements to facilitate ease of movement of people, goods and services.

Northern Ireland peace process

There have been concerns, raised by a range of politicians from Irish Republicans in the left-wing Sinn Fein party which is active throughout Ireland to the Conservative former prime minister John Major, that May's government could not play the role of "honest broker" in talks in Northern Ireland if it has formal ties with the DUP.

The 1998 Good Friday Agreement commits the UK and Irish Governments to demonstrate "rigorous impartiality" in all their dealings with the different groups in Northern Ireland.

The power sharing agreement involving the DUP and Sinn Fein at the Stormont assembly in Northern Ireland collapsed in March over the DUP's refusal to hold a public inquiry into a renewable heating funding scandal.

Sinn Fein in London

Sinn Fein parliamentarians were also in London on Thursday to raise concerns with the British government that the Conservative-DUP deal could prevent the restoration of power sharing in Northern Ireland.

Ahead of the talks, Michelle O'Neill, Sinn Fein's leader in the Northern Ireland Stormont assembly, said: "I will be making it very clear that any deal between the Tories and the DUP cannot be allowed to undermine the Good Friday and subsequent agreements."

O'Neill said in a statement that both London and Dublin must "recommit to the word, spirit and implementation of the Good Friday Agreement" if power sharing at Stormont is to be re-established, she said.

"Progress will not come from a deal between the DUP and Tories to prop up a Government in Westminster with an austerity and Brexit agenda," the Sinn Fein leader added.

After talks with Prime Minister May, Sinn Fein President Gerry Adams said via Twitter: "We told the British PM that her government is in default of the Good Friday [Agreement]. It also needs to ensure that any arrangement with the DUP is public."

Senior politics lecturer at Surrey University Simon Usherwood raised the same issues: "The main concern is going to be that if there is a Conservative-DUP deal, then can the British government continue to play the role of a honest broker in the restoration of a Northern Ireland executive," he queried. "The risk is that Northern Ireland continues to fail to find solutions, and potentially the peace process unwinds," Usherwood said.